How about a Supertigre G-90 (2 cycle)

I know, I know keep it light.... Mine balanced perfectly even with the big 90 up front- swinging a 15x4 Zinger @ 9,900 RPM's on 5%
I would bet the Saito-82 is about perfect but I got a kick out of TOTALLY overpowering this airplane- and yes, modifying the engine mount/firewall/blind nut set-up was a hassle---
Take care all you Funtana junkies!